I have become fond of the Mikuni flat slide carbs. They are very nice, and they are not very expensive. The round slide ones are even less expensive.

I would say that a 30mm or 32mm Mikuni would be fine. In fact, a 32mm Mikuni Flat Slide carb is what we normally recommend for all Bullets, but we are taking into account that they will stick with the one carb as they upgrade their power levels. IF you have no power upgrade plans which include increased breathing of the cylinder head, then a 30mm would do fine.

You'll need to re-jet any of these carbs, because they come jetted for other bikes which are not like ours.30 pilot, p6 needle jet, 190 main would probably be a good jetting start for a stock bike and a Mikuni TM32-1.Pilot jets are 22/210 typeNeedle jets are 389 typeMain jets are 4/042 type.

They are affordable,effective,efficient and throttle response is improved as is performance. They give good results on both stock and modified engines frim mild to wild.

Noteworthy to mention that the slide is not truly flat but more of a D shape.This gives the crisp operation of a true flat slide with the forgiveness of a round slide. Also the carbs venturi is oval rather than circular. The lower portion is 28 or 30mm for stellar low low rpm performance and it tapers up to 30 or 32mm for improved flow at mid range and top end.

With a free flow intake and exhaust mild and hot ignition a 30mm is the ticket.

With the above plus bigger bore and hotter cams a 32mm would be better.

Logged

I can break it better,,,,at night, in the rain, on the trail,, 20 miles from nowhere.

REA #136

"TIMEX", the '06 Iron Barrel Military that takes me everywhere I want to go... and some places I shouldn't.

The genuine Mikuni carbs are flatslides. The popular Keihan copies (PWK, OKO) are "D" slides. Here's a picture of a Mikuni VM-28/418 Flatslide (TM-28) test fitted on my '07 Military. There's plenty of room if you use a Mikuni flange. I've since added a phenolic heat spacer for a Triumph I found online. Using the original manifold with radiator hose placed the carb up against the Tank mount bolt. The fuel line needed a careful reroute to behind the carb.Edit: I turned the choke around to the right side like the original roundslide it came with.It's only a 28mm but the throttle response improved tremendously. I'd have gone 30mm, but I had the 28 sitting on the shelf.

Thanks for the responses. So Nfield Gear has a mikuni carb kit which looks pretty complete for an iron barrel motor. The blurb does not say what it has for jets. Do you guys know if it comes through properly jetted? I am assuming it will if they are selling it as a replacement kit for thes bikes? Bad assumption?Duncan